Citrobacter rodentium Induces Tissue-Resident Memory CD4+ T Cells.

Tissue-resident memory T cells (TRM cells) are a novel population of tissue-restricted antigen-specific T cells. TRM cells are induced by pathogens and promote host defense against secondary infections. Although TRM cells cannot be detected in circulation, they are the major memory CD4+ and CD8+ T-cell population in tissues in mice and humans. Murine models of CD8+ TRM cells have shown that CD8+ TRM cells maintain tissue residency via CD69 and though tumor growth factor ß-dependent induction of CD103. In contrast to CD8+ TRM cells, there are few models of CD4+ TRM cells. Thus, much less is known about the factors regulating the induction, maintenance, and host defense functions of CD4+ TRM cells. Citrobacter rodentium is known to induce IL-17+ and IL-22+ CD4+ T cells (Th17 and Th22 cells, respectively). Moreover, data from IL-22 reporter mice show that most IL-22+ cells in the colon 3 months after C. rodentium infection are CD4+ T cells. This collectively suggests that C. rodentium may induce CD4+ TRM cells. Here, we demonstrate that C. rodentium induces a population of IL-17A+ CD4+ T cells that are tissue restricted and antigen specific, thus meeting the criteria of CD4+ TRM cells. These cells expand and are a major source of IL-22 during secondary C. rodentium infection, even before the T-cell phase of the host response in primary infection. Finally, using FTY 720, which depletes circulating naive and effector T cells but not tissue-restricted T cells, we show that these CD4+ TRM cells can promote host defense.

Modelling dysplasia detection in ulcerative colitis: clinical implications of surveillance intensity.

BACKGROUND: Endoscopic surveillance of chronic colitis uses random biopsies to find dysplastic fields. Enhanced endoscopic methods are more sensitive for dysplasia detection, but their specificity for colorectal cancer risk is unknown. AIMS: To develop a mathematical model of the sensitivity of random biopsy surveillance, and determine the implications of negative, a single positive, or multiple positive biopsies for dysplasia, and compare the detection threshold to that detectable by enhanced endoscopy. METHODS: Using mathematical modelling, we calculated the confidence level with which dysplasia can be excluded, the dysplastic field size detection threshold, the predicted area of a dysplastic field, and the number of biopsies needed for a given dysplasia detection threshold and confidence level. RESULTS: 32 random biopsies provide only 80% confidence that dysplasia involving > or =5% of the colon can be detected. When a single biopsy of 18 is dysplastic, this predicts a dysplastic area (89 cm(2)) several orders of magnitude greater than dysplastic fields that are readily detectable by enhanced endoscopy (1 cm diameter), and the predicted field size increases rapidly with multiple positive biopsies. CONCLUSIONS: Random biopsy surveillance is sufficiently sensitive to detect large dysplastic fields with significant colorectal cancer risk. Enhanced endoscopy can detect much smaller dysplastic fields, but these have unknown (perhaps much lower) colorectal cancer risk. Small dysplastic fields should not be assumed to indicate a high colorectal cancer risk that warrants colectomy. Prospective studies are needed to define the colorectal cancer risk and optimal management of small dysplastic lesions.

A meta-analysis of rectal NSAIDs in the prevention of post-ERCP pancreatitis.

BACKGROUND: Several pharmacological agents for the prevention of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) have been studied. Clinical trials evaluating the protective effect of non-steroidal anti-inflammatory drugs (NSAIDs) have yielded inconclusive results. AIM: To perform a meta-analysis of studies evaluating the effect of prophylactic rectal NSAIDs on PEP. METHODS: By searching Medline, Embase, meeting abstracts and bibliographies, two independent reviewers systematically identified prospective randomised controlled trials (RCTs) examining the effect of rectally administered prophylactic NSAIDs on the incidence of PEP pancreatitis. A meta-analysis of these clinical trials was performed. RESULTS: Four RCTs, enrolling a total of 912 patients, have been published. Meta-analysis of these studies demonstrates a pooled relative risk for PEP after prophylactic administration of NSAIDs of 0.36 (95% CI 0.22 to 0.60); patients who received NSAIDs in the periprocedural period were 64% less likely to develop pancreatitis and 90% less likely to develop moderate to severe pancreatitis. The pooled number needed to treat with NSAIDs to prevent one episode of pancreatitis is 15 patients. No adverse events attributable to the use of NSAIDs were reported in any of the clinical trials. CONCLUSION: In this meta-analysis, prophylactic NSAIDs were effective in preventing PEP. Widespread prophylactic administration of these agents may significantly reduce the incidence of PEP, resulting in major clinical and economic benefit. Given current scepticism regarding the efficacy of any prophylactic medication for ERCP, additional multicentre studies are needed for confirmation prior to widespread adoption of this strategy.

Predicting corticosteroid-free endoscopic remission with vedolizumab in ulcerative colitis.

BACKGROUND: Vedolizumab is an effective therapy for ulcerative colitis (UC), but costly and slow to work. New clinical responses occur after 30 weeks of therapy. AIMS: To enable physicians, patients, and insurers to predict whether a patient with UC will respond to vedolizumab at an early time point after starting therapy. METHODS: The clinical study data request website provided the phase 3 clinical trial data for vedolizumab. Random forest models were trained on 70% and tested on 30% of the data to predict corticosteroid-free endoscopic remission at week 52. Models were constructed using baseline data, or data through week 6 of vedolizumab therapy from 491 subjects. RESULTS: The AuROC for prediction of corticosteroid-free endoscopic remission at week 52 using baseline data was only 0.62 (95% CI: 0.53-0.72), but was 0.73 (95% CI: 0.65-0.82) when using data through week 6. A total of 47% of subjects were predicted to be remitters, and 59% of these subjects achieved corticosteroid-free endoscopic remission, in contrast to 21% of the predicted non-remitters. A week 6 prediction using FCP ≤234 µg/g was nearly as accurate. CONCLUSIONS: A machine learning algorithm using laboratory data through week 6 of vedolizumab therapy was able to accurately identify which UC patients would achieve corticosteroid-free endoscopic remission on vedolizumab at week 52. Application of this algorithm could have significant implications for clinical decisions on whom to continue on this costly medication when the benefits of the vedolizumab are not clinically apparent in the first 6 weeks of therapy.

The quantitative validation of non-endoscopic disease activity indices in ulcerative colitis.

BACKGROUND: Ulcerative colitis disease activity indices have not been formally validated. AIM: To analise quantitatively the psychometric and performance validity of two non-endoscopic indices for ulcerative colitis, the Simple Clinical Colitis Activity Index and the Seo Index. METHODS: In 66 patients with ulcerative colitis, the measurement of disease activity was repeated with the two non-endoscopic indices, St Mark's Index, and the Inflammatory Bowel Disease Questionnaire. Psychometric validity was evaluated by measuring the content, construct, criterion-convergent and criterion-predictive validity on a 0-1 scale. Performance validity was evaluated by measuring the reproducibility and responsiveness on a 0-1 scale. RESULTS: The Simple Clinical Colitis Activity Index had good to excellent psychometric and performance validity, while the Seo Index had moderate to excellent psychometric validity and moderate to good performance validity. The Simple Clinical Colitis Activity Index had weaknesses in content validity and in responsiveness. The Seo Index had weaknesses in content validity, construct validity and responsiveness. CONCLUSIONS: These two non-endoscopic indices for ulcerative colitis have good psychometric and performance validity, and are now the most rigorously validated disease activity indices for ulcerative colitis. The Simple Clinical Colitis Activity Index appears to have better overall validity. Quantitative evaluation identifies weaknesses in disease activity indices, and can lead to better disease activity indices for ulcerative colitis.

Magnetic resonance enterography is feasible and reliable in multicenter clinical trials in patients with Crohn's disease, and may help select subjects with active inflammation.

BACKGROUND: Reliable tools for patient selection are critical for clinical drug trials. AIM: To evaluate a consensus-based, standardised magnetic resonance enterography (MRE) protocol for selecting patients for inclusion in Crohn's disease (CD) multicenter clinical trials. METHODS: This study recruited 20 patients [Crohn's Disease Activity Index (CDAI) scores: <150 (n = 8); 150-220 (n = 4); 220-450 (n = 8)], to undergo ileocolonoscopy and two MREs (with and without colonic contrast) within a 14-day period. Procedures were scored centrally using, Magnetic Resonance Index of Activity (MaRIA), and both Crohn's Disease Endoscopic Index of Severity (CDEIS) and Simplified Endoscopic Score (SES-CD). RESULTS: 37 MREs were acquired. Both MREs were evaluable in 16 patients for calculation of test-retest and inter-reader reliability scores. The MaRIA scores for the terminal ileum had excellent test-retest and inter-reader reliability, with correlations >0.9. The proximal ileum showed strong within-reader agreement (0.90-0.96), and fair between-reader agreement (0.59-0.72). MRE procedures were tolerable. MaRIA scores correlated with CDEIS and SES-CD (0.63 and 0.71), but not with CDAI (0.34). MRE identified 3 patients with intra-abdominal complications, who would otherwise have been included in clinical trials. Furthermore, both MRE and ileocolonoscopy identified active bowel wall inflammation in 2 patients with CDAI <150, and none in 1 patient with CDAI > 220. Data quality was good/excellent in 85% of scans, and fair or better in 96%. CONCLUSIONS: Magnetic resonance enterography of high-quality and reproducibility was feasible in a global multi- centre setting, with evidence for improved selectivity over CDAI and ileocolonoscopy in identifying appropriate CD patients for inclusion in therapeutic intervention trials.

Systematic review: the epidemiology of ischaemic colitis.

BACKGROUND: Ischaemic colitis has been associated with co-morbid conditions, medications, vascular surgery and advanced age in case reports and case series. Few data exist on the baseline incidence in the general population or on the increased risk imposed by these risk factors. AIM: To systematically review the literature regarding the incidence, prevalence and risk factors for ischaemic colitis. METHODS: Searches of bibliographic databases were performed independently by two investigators. Studies were included if they used population-based samples, disease-specific population samples or case-control population-based samples of adults with ischaemic colitis, and reported the incidence, prevalence or risk factors for ischaemic colitis. Eligible articles were reviewed and data were abstracted in a duplicate, independent manner. RESULTS: Four studies were identified that reported the general population incidence and four that reported the disease-specific population incidence. The incidence of ischaemic colitis in general populations ranged from 4.5 to 44 cases per 100 000 person-years. The risk was increased two- to four-fold by either prevalent irritable bowel syndrome or chronic obstructive pulmonary disease. The risk was also increased in females and in subjects of 65 years and older. CONCLUSIONS: Ischaemic colitis is uncommon in the general population. The effect sizes of the most commonly reported risk factors have not been adequately quantified in population-based studies.

Liver transplantation in acute liver failure.

Acetaminophen and idiosyncratic drug induced hepatotoxicity are the most commonly identified etiologies of acute liver failure in Western countries. Infectious complications and cerebral edema remain the leading causes of death. Moderate hypothermia and other medical interventions may improve cerebral edema in selected patients with acute liver failure. In addition, pilot studies suggest that recombinant factor VIIa infusions may allow for the safe placement of intracranial pressure monitoring devices in patients with cerebral edema and severe coagulopathy. Auxiliary liver transplantation and bioartificial liver devices offer the hope of temporary liver support for selected patients with a high likelihood of native liver regeneration. Prognostic survival models that include arterial lactate levels may improve our ability to identify acetaminophen overdose patients in urgent need of liver transplantation. The lower 1-year patient survival following liver transplantation for acute liver failure compared to chronic liver failure (60 vs 80%) is in part due to the emergent nature of surgery, concomitant vital organ failure, and the higher incidence of immunologically mediated graft dysfunction. Vaccination against hepatotrophic viruses and other public health measures designed to minimize the incidence of both intentional and non-intentional acetaminophen overdose may help reduce the future incidence of acute liver failure. In the meanwhile, it is recommended that acute liver failure patients be managed in experienced centers with ready access to liver transplantation to optimize outcomes in this rare but frequently fatal illness.

Systematic review with network meta-analysis: the efficacy of anti-TNF agents for the treatment of Crohn's disease.

BACKGROUND: Anti-tumour necrosis factor-alpha agents (anti-TNF) are effective therapies for the treatment of Crohn's disease (CD), but their comparative efficacy is unknown. AIM: To perform a network meta-analysis comparing the efficacy of anti-TNF therapies in CD. METHODS: After screening 506 studies, reviewers extracted information on 10 studies. Traditional meta-analysis (TMA) was used to compare each anti-TNF agent to placebo. Bayesian network meta-analysis (NMA) was performed to compare the effects of anti-TNF agents to placebo. In addition, sample sizes for comparative efficacy trials were calculated. RESULTS: Compared to placebo, TMA revealed that anti-TNF agents result in a higher likelihood of induction of remission and response (RR: 1.66, 95% CI: 1.17-2.36 and RR: 1.43, 95% CI: 1.17-1.73, respectively) as well as maintenance of remission and response (RR: 1.78, 95% CI: 1.51-2.09 and RR: 1.68, 95% CI: 1.46-1.93, respectively). NMA found nonsignificant trends between infliximab and adalimumab or certolizumab pegol. Among subcutaneous therapies, NMA demonstrated superiority of adalimumab to certolizumab pegol for induction of remission (RR: 2.93, 95% CrI: 1.21-7.75). Sample size calculations suggest that adequately powered head-to-head comparative efficacy trials would require greater than 3000 patients. CONCLUSIONS: All anti-TNF agents are effective for induction and maintenance of response and remission in the treatment of CD. Although adalimumab is superior to certolizumab pegol for induction of remission, there is no evidence of clinical superiority among anti-TNF agents. Head-to-head trials among the anti-TNF agents are impractical in terms of size and cost.

Systematic review with network meta-analysis: the efficacy of anti-tumour necrosis factor-alpha agents for the treatment of ulcerative colitis.

BACKGROUND: Antibodies against tumour necrosis factor-alpha (anti-TNF) are effective therapies in the treatment of ulcerative colitis (UC), but their comparative efficacy is unknown. AIM: To perform a network meta-analysis comparing the efficacy of anti-TNF agents in UC. METHODS: After screening 506 studies, reviewers extracted information on seven studies. Traditional meta-analysis (TMA) was used to compare each anti-TNF agent to placebo. Bayesian network meta-analysis (NMA) was performed to compare the effects of anti-TNF agents to placebo. In addition, sample sizes for comparative efficacy trials were calculated. RESULTS: Compared to placebo, TMA revealed that anti-TNF agents result in a higher likelihood of induction of remission and response (RR: 2.45, 95% CI: 1.72-3.47 and RR: 1.65, 95% CI: 1.37-1.99 respectively) as well as maintenance of remission and response (RR: 2.00, 95% CI: 1.52-2.62 and RR: 1.76, 95% CI: 1.46-2.14 respectively). Individually, infliximab, adalimumab and goliumumab resulted in a higher likelihood of induction and maintenance for both remission and response. NMA found nonsignificant trends in comparisons of the individual agents. The required sample sizes for direct head-to-head trials between infliximab and adalimumab for induction and maintenance are 174 and 204 subjects respectively. CONCLUSIONS: This study demonstrates that, compared to placebo, infliximab, adalimumab and golimumab are all effective for the induction and maintenance of remission in ulcerative colitis. However, network meta-analysis demonstrates that no single agent is clinically superior to the others and therefore, other factors such as cost, safety, route of administration and patient preference should dictate our choice of anti-TNF agents. A randomised comparative efficacy trial between infliximab and adalimumab in UC is of practical size and should be performed.

Review article: defining remission in ulcerative colitis.

BACKGROUND: There is no international agreement on scoring systems used to measure disease activity in ulcerative colitis, nor is there a validated definition for disease remission. AIM: To review the principles and components for defining remission in ulcerative colitis and propose a definition that will help improve patient outcomes. METHODS: A review of current standards of remission from the perspective of clinical trials, guidelines, clinical practice and patients was conducted by the authors. Selected literature focused on the components of a definition of remission, the utility of a definition and treatment strategies, based on current definitions. RESULTS: Different definitions of remission affect the assessment of outcome and make it difficult to compare trials. In the clinic, endoscopy is rarely used to confirm remission, because mucosal healing has only recently begun to be related to the duration of subsequent remission in a way that will affect clinical practice. Histopathology may be the ultimate arbiter of mucosal healing. There is no agreement on the definition of remission in current guidelines. Patient-defined remission may predict endoscopic remission, but has yet to be shown to predict duration of remission. CONCLUSIONS: A standard based on clinical symptoms and endoscopy is proposed. Histopathology is a third dimension of remission that may have prognostic value. The definition of remission should help predict long-term outcome. The expectations of patients and their physicians need to be raised, as the goal of treatment of active ulcerative colitis should be to induce remission.

Systematic review: impact of non-adherence to 5-aminosalicylic acid products on the frequency and cost of ulcerative colitis flares.

BACKGROUND: Ulcerative colitis (UC) can be maintained in remission with 5-aminosalicylic acid (5-ASA) medications, but frequent non-adherence by patients who are feeling well has been associated with more frequent flares of colitis. AIM: To perform a systematic review of the published literature and unpublished randomized clinical trials (RCTs) regarding the impact of non-adherence with 5-ASA medications on the incidence of UC flares and costs of care. METHODS: A search of MEDLINE, EMBASE and the Cochrane databases was performed. Prospective studies of UC maintenance with 5-ASAs in adults were selected if they included data on adherence and disease flares. Studies using insurance claims data to estimate the impact of non-adherence on cost of care were included. Data from unpublished RCTs were obtained from the FDA with a request under the Freedom of Information Act. RESULTS: The relative risk for flare in non-adherent vs. adherent patients ranged from 3.65 to infinity. Data were obtained from six unpublished 5-ASA RCTs, but none measured the impact of adherence on disease activity. The comorbidity-adjusted annual costs of care in adherent patients were 12.5% less than in non-adherent patients, despite increased medication expenditures. CONCLUSIONS: A substantial proportion of UC flares and medical costs of UC are attributable to 5-ASA non-adherence. As non-adherence to 5-ASA medications is common, cost-effective strategies to improve adherence are needed. The impact of adherence on disease activity should be measured in RCTs of all inflammatory bowel disease treatments.

The effect of mesalazine therapy on quality of life in patients with mildly and moderately active ulcerative colitis.

BACKGROUND: Ulcerative colitis (UC) has a major impact on the quality of life (QoL) of affected patients. Patient-reported outcomes have not been thoroughly evaluated in patients with UC receiving oral mesalazine (mesalamine). AIM: To examine the effect of mesalazine on QoL of patients with mildly and moderately active UC and assess the time course of change, baseline disease severity, mesalazine dose and responder status on QoL parameters. METHODS: Inflammatory Bowel Disease Questionnaire (IBDQ) data were combined from two double-blind, randomized, multicentre, active-controlled trials assessing 2.4 and 4.8 g/day oral delayed-release mesalazine in 687 patients. Mean score changes from baseline were compared at 3 and 6 weeks and effects of baseline severity, mesalazine dose and response to therapy were examined. RESULTS: Mesalazine significantly improved IBDQ scores at 3 and 6 weeks (mean increase, 29.6 and 39.7 points, respectively; P < 0.0001 for both). Improvement was greater for patients with moderate disease. Greater week 6 changes occurred in clinical responders than nonresponders (50.1 vs. 23.6 points, respectively; P < 0.0001). CONCLUSIONS: Delayed-release oral mesalazine produces significant clinical and statistical improvements in QoL of patients with UC by 3 weeks, with further improvement at 6 weeks.

Threefold increased risk of infertility: a meta-analysis of infertility after ileal pouch anal anastomosis in ulcerative colitis.

BACKGROUND: Increased infertility in women has been reported after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis but reported infertility rates vary substantially. AIMS: (1) To perform a systematic review and meta-analysis of the relative risk of infertility post-IPAA compared with medical management; (2) to estimate the rate of infertility post-IPAA; and (3) to identify modifiable risk factors which contribute to infertility. METHODS: Medline, EMBASE, Current Contents, meeting abstracts, and bibliographies were searched independently by two investigators. The titles and abstracts of 189 potentially relevant studies were reviewed; eight met the criteria and all data were extracted independently. Consensus was achieved on each data point, and fixed effects meta-analyses, a funnel plot, and sensitivity analyses were performed. RESULTS: The initial meta-analysis of eight studies had significant heterogeneity (p = 0.004) due to one study with very high preoperative infertility (38%). When this study was omitted, the relative risk of infertility after IPAA was 3.17 (2.41-4.18), with non-significant heterogeneity. The weighted average infertility rate in medically treated ulcerative colitis was 15% for all seven studies, and the weighted average infertility rate was 48% after IPAA (50% if all eight studies are included). We were unable to identify any procedural factors that consistently affected the risk of infertility. CONCLUSIONS: IPAA increases the risk of infertility in women with ulcerative colitis by approximately threefold. Infertility, defined as achieving pregnancy in 12 months of attempting conception, increased from 15% to 48% in women post-IPAA for ulcerative colitis. This provides a basis for counselling patients considering colectomy with IPAA. Further studies of modifiable risk factors are needed.

Patient defined dichotomous end points for remission and clinical improvement in ulcerative colitis.

BACKGROUND AND AIMS: Ulcerative colitis disease activity indices offer good statistical power but small changes in these indices may not be clinically important. There are no validated definitions of remission or of significant improvement for these indices. The use of clinically important end points would strengthen the validity of study outcomes. Our aims were to identify objective end points in standard disease activity indices for remission and for improvement in ulcerative colitis. METHODS: Sixty six consecutive patients with ulcerative colitis provided information about remission status and their disease activity. At a return visit 1-14 months later, these patients provided information about the change in their disease activity, and non-invasive indices were measured. RESULTS: Specific objective end points for determining remission with four standard indices and a quality of life instrument were determined (St Mark's <3.5, ulcerative colitis disease activity index <2.5, simple clinical colitis activity index (SCCAI) <2.5, Seo <120, and inflammatory bowel disease quality of life index (IBDQ) >205). These cut offs also identified patients who met a regulatory definition of remission. Specific objective end points for clinical improvement in two non-invasive indices and a quality of life instrument were determined with good sensitivity and specificity (SCCAI decrease >1.5, Seo decrease >30, IBDQ increase >20). CONCLUSIONS: We found specific cut off values for disease activity indices that identify patients who have significantly improved or achieved remission in an objective, sensitive, and specific manner. These cut offs should help in the interpretation of the outcomes of clinical trials in ulcerative colitis.